It couldn't have added *that* much more. Off-hands are already at 50% damage, 75% with full DW. Even with full DW, it's just 37.5% weapon damage extra. Of course you can Devastate on every GCD, but you can't sustain enough rage to keep it up. With my warrior I can't Devastate on every cooldown when I'm soloing, even if I start out with a full rage bar... and I should be getting more rage while I'm on my own as I presumably won't get hit while in a group. Though I haven't tested it specifically for that purpose, so I might be remembering wrong... probably added some heroic strikes. I'll have to do so.
Earthen Ring-EU:
Taelas -- 60 Human Protection Warrior; Shaleen -- 52 Human Retribution Paladin; Raethal -- 51 Worgen Guardian Druid; Szar -- 50 Human Fire Mage; Caethan -- 60 Human Blood Death Knight; Danee -- 41 Human Outlaw Rogue; Ainsleigh -- 52 Dark Iron Dwarf Fury Warrior; Mihena -- 44 Void Elf Affliction Warlock; Chiyan -- 41 Pandaren Brewmaster Monk; Threkk -- 40 Orc Fury Warrior; Alliera -- 41 Night Elf Havoc Demon Hunter;
Darkmoon Faire-EU:
Sieon -- 45 Blood Elf Retribution Paladin; Kuaryo -- 51 Pandaren Brewmaster Monk
Taelas -- 60 Human Protection Warrior; Shaleen -- 52 Human Retribution Paladin; Raethal -- 51 Worgen Guardian Druid; Szar -- 50 Human Fire Mage; Caethan -- 60 Human Blood Death Knight; Danee -- 41 Human Outlaw Rogue; Ainsleigh -- 52 Dark Iron Dwarf Fury Warrior; Mihena -- 44 Void Elf Affliction Warlock; Chiyan -- 41 Pandaren Brewmaster Monk; Threkk -- 40 Orc Fury Warrior; Alliera -- 41 Night Elf Havoc Demon Hunter;
Darkmoon Faire-EU:
Sieon -- 45 Blood Elf Retribution Paladin; Kuaryo -- 51 Pandaren Brewmaster Monk